Noise Cancellation Driver ICs Feature Zero Audible Hiss

Posted Dec 10, 2013 4:37:44 PM |
Posted

The new AS3435 and AS3415 ANC speaker drivers from ams AG pave the way for a new generation of noise cancellation stereo headsets with zero audible hiss. They are also the first active noise cancellation (ANC) ICs with integrated bypass functionality, enabling headset manufacturers to fashion sleeker and lower-cost housing designs. The AS3435 and AS3415 also include bass boost equalization capability, eliminating the need for a discrete signal processing IC for this purpose.

The AS3435 (for feedback systems) and AS3415 (for feed-forward systems) incorporate new ultra-low noise amplifiers with a 900 nV input-referred noise floor, eliminating audible high-frequency hiss when paired with low-noise microphones. They also feature 35 mW of stereo output power with THD+N of 0.1% into a 32 Ω load and a typical signal-to-noise ratio greater than 110 dB.

The integrated bypass function of the new ANC ICs enables simplification of the mechanical design of headset housings. Conventional ANC headsets require a mechanical switch to select bypass mode when the headset’s battery is completely discharged. This switch constrains the design of the headset’s housing and circuit board. With the AS3435 and AS3415, the music signal can pass through the ANC chipset without any power source connected to the device.

The devices’ analog implementation of noise cancellation results in power consumption often two or three times lower than equivalent digital solutions. Featuring typical power consumption of 10 mW at 1.5 V in noise cancellation mode, either device can support operation for more than 100 hours from a single AAA battery.

An evaluation kit for the AS3435 and AS3415 is available online from ams.